Which of the following is an incorrect statement?

• A

  The term “chemical knife” is used for restriction endonuclease.

• B

  In the case of EcoRI, R represents the genus of the prokaryote from which the enzyme is obtained.

• C

  The linking of the antibiotic-resistance gene with the plasmid vector became possible with enzyme ligase.

• D

  The substrate for restriction enzyme is double-stranded DNA.